Optical Tweezers: Application Note Videos

A number of experiments were commissioned by Elliot Scientific to test and demonstrate the capabilities of the standard E3500 Optical Tweezers system. These were undertaken by a team at St. Andrews University and are presented as a series of Application Notes with accompanying videos.

These recordings can be viewed below, on YouTube, or downloaded as Windows Movie files from the Documents tab above.

Videos accompanying Application Note 2:

Trapping and Manipulation of Multiple Cells and Cell Adherence

5x5 Grid Manipulation - This video shows a trapped 5x5 array of 2 µm polymer beads. It demonstrates expansion, contraction, and rotation as well as movement of a single bead in and around the 25 trapped beads. Video speed is 2x.

TRA Array - This video shows 3x3 trapping of algae, demonstrating Z trapping and then expansion, contraction, and rotation of the cell array. Video is recorded at 2x speed.

HEK Adhesion - Two HEK (human embryonic kidney) cells were held in circular trap arrays and brought into contact so that they became stuck together. This cell coupling is demonstrated until one of the cells is dropped from the trap and the force of its sinking pulls it away from the other cell.

RBC Array - This video, shot at 2x speed, shows 3x3 trapping of red blood cells. It demonstrates expansion, contraction, and rotation of the cell array as well synchronised rotation obtained by using two sets of 3x3 traps to capture both ends of the 'donut' of each cell.

RBC Flip - This video, shot at normal speed, shows a small amount of stretching of a red blood cell but, more importantly, shows the handy trick of 'flipping' by using a circular array of traps, so that it lies parallel to the detection plane. The cell flips onto its side during stretching due to insufficient power in the ring array to overcome the cells natural preference to twist when trapped between two beads.

Videos accompanying Application Note 3:

Cell Stretching

RBC Stretch - 1 - Both of these movies, recorded at 2x speed, show stretching of the same red blood cell. The cell is positioned parallel to the detector using a circular array of traps. This is because these cells prefer to flip onto their side when only the beads are trapped. A different laser power is used in each video to show different amounts of stretching - which is not noticeably visible between the two videos. Eventually the cell stops stretching and snaps back to its original shape, pulling the bead used for stretching out of its trap.

RBC Stretch - 2

Videos accompanying Application Note 4:

Photoporation and Transfection of Cells with Pulsed Laser Light

HL60 Optoinjection - 1 - HL60 (human leukemia) cells were used in these two optoinjection/photoporation studies. A co-aligned 800 nm, 200 fs laser beam was used for poration, with an electronic shutter defining the dosage - 40 ms provided a gentle push and made fewer bubbles, while 120 ms was a massive blast that usually destroyed the cells.